Question 1

Balance the following equation: C8H18O3(l)  + O2(g)  → H2O(g)  + CO2(g)

Accepted Answer

A)  C 8H 18O 3( l) + 8O 2( g) → 9H 2O( g) + 8CO 2( g) 
B)  C 8H 18O 3( l) + 11O 2( g) → 9H 2O( g) + 8CO 2( g) 
C)  2C 8H 18O 3( l) + 22O 2( g) → 9H 2O( g) + 16CO 2( g) 
D)  C 8H 18O 3( l) + 13O 2( g) → 18H 2O( g) + 8CO 2( g) 
E)  2C 8H 18O 3( l) + 17O 2( g) → 18H 2O( g) + 16CO 2( g) F) C) and E)
G) D) and E)

Question 2

Phosphorus pentachloride, PCl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl5.

Accepted Answer

A)  5.38 mol
B)  3.55 mol
C)  0.583 mol
D)  0.282 mol
E)  0.186 molF) D) and E)
G) A) and E)

Question 3

Methanol (CH4O)  is converted to bromomethane (CH3Br)  as follows: CH4O + HBr → CH3Br + H2O
If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr, what is the percentage yield?

Accepted Answer

A)  40.9%
B)  82.6%
C)  100%
D)  121%
E)  245%F) A) and E)
G) A) and D)

Question 4

Household sugar, sucrose, has the molecular formula C12H22O11. What is the percent of carbon in sucrose, by mass?

Accepted Answer

A)  26.7%
B)  33.3%
C)  41.4%
D)  42.1%
E)  52.8%F) B) and C)
G) A) and E)

Question 5

The formula CH3O0.5 is an example of an empirical formula.

Accepted Answer

A) True 
 B)False

Question 6

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Accepted Answer

A)  Gd 2O 3
B)  Gd 3O 2
C)  Gd 3O 4
D)  Gd 4O 3
E)  GdOF) B) and E)
G) A) and D)

Question 7

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.
A)118.15 g/mol
B)99.15 g/mol
C)78.07 g/mol
D)59.08 g/mol
E)50.01 g/mol

Accepted Answer

A) True 
 B)False

Question 8

Lead (II)  nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO3) 2.

Accepted Answer

A)  107 g
B)  90.8 g
C)  87.0 g
D)  83.4 g
E)  62.6 gF) A) and C)
G) D) and E)

Question 9

A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula.

Accepted Answer

A)  CrSi 3
B)  Cr 2Si 3
C)  Cr 3Si
D)  Cr 3Si 2
E)  Cr 2SF) D) and E)
G) A) and E)

Question 10

One mole of methane (CH4) contains a total of 3 × 1024 atoms.

Accepted Answer

A) True 
 B)False

Question 11

In a blast furnace, elemental iron is produced from a mixture of coke (C) , iron ore (Fe3O4) , and other reactants. An important reaction sequence is 2C(s)  + O2(g)  → 2CO(g) 
Fe3O4(s)  + 4CO(g)  → 3Fe(l)  + 4CO2(g) 
How many moles of iron can be formed in this sequence when 1.00 mol of carbon, as coke, is consumed?

Accepted Answer

A)  6.00 mol Fe
B)  3.00 mol Fe
C)  1.33 mol Fe
D)  1.25 mol Fe
E)  0.750 mol FeF) B) and D)
G) A) and D)

Question 12

Constitutional (structural) isomers have the same molecular formula but different structural formulas.

Accepted Answer

A) True 
 B)False

Question 13

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO2 and H2O, respectively, which are collected in the absorbers.

Accepted Answer

A) True 
 B)False

Question 14

Potassium chlorate (used in fireworks, flares, and safety matches)  forms oxygen and potassium chloride when heated. KClO3(s)  → KCl(s)  + O2(g)  [unbalanced]
How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Accepted Answer

A)  223 g
B)  99.1 g
C)  10.3 g
D)  6.86 g
E)  4.60 gF) B) and D)
G) A) and C)

Question 15

Constitutional (structural) isomers have the same empirical formula but different molecular formulas.

Accepted Answer

A) True 
 B)False

Question 16

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Accepted Answer

A)  HNO
B)  H 2NO 2
C)  HN 6O 16
D)  HN 16O 7
E)  H 2NO 3F) A) and B)
G) A) and E)

Question 17

Lead(II)  sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form lead(II)  sulfate and water. How many grams of hydrogen peroxide are needed to react completely with 265 g of lead(II)  sulfide?

Accepted Answer

A)  151 g
B)  123 g
C)  50.3 g
D)  37.7 g
E)  9.41 gF) A) and E)
G) A) and D)

Question 18

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Accepted Answer

A)  BrF
B)  BrF 2
C)  Br 2F 3
D)  Br 3F
E)  BrF 3F) C) and D)
G) A) and B)

Question 19

Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride.

Accepted Answer

A)  Potassium is the limiting reactant; 2.47 g of chlorine remain.
B)  Potassium is the limiting reactant; 7.23 g of chlorine remain.
C)  Chlorine is the limiting reactant; 4.64 g of potassium remain.
D)  Chlorine is the limiting reactant; 2.70 g of potassium remain.
E)  No limiting reagent: the reactants are present in the correct stoichiometric ratio.F) All of the above
G) A) and B)

Question 20

Balance the following equation for the combustion of benzene: C6H6(l)  + O2(g)  → H2O(g)  + CO2(g)

Accepted Answer

A)  C 6H 6( l) + 9O 2( g) → 3H 2O( g) + 6CO 2( g) 
B)  C 6H 6( l) + 9O 2( g) → 6H 2O( g) + 6CO 2( g) 
C)  2C 6H 6(l) + 15O 2(g) → 6H 2O(g) + 12CO 2( g) 
D)  C 6H 6( l) + 15O 2( g) → 3H 2O( g) + 6CO 2( g) 
E)  2C 6H 6( l) + 9O 2( g) → 6H 2O( g) + 12CO 2( g) F) A) and D)
G) A) and C)

Exam 3: Stoichiometry of Formulas and Equations

Correct Answer
verified

Constitutional (structural) isomers have the same empirical formula but different molecular formulas.

Correct Answer
verified

Lead(II) sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form lead(II) sulfate and water. How many grams of hydrogen peroxide are needed to react completely with 265 g of lead(II) sulfide?

Correct Answer
verified

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Correct Answer
verified

Potassium chlorate (used in fireworks, flares, and safety matches) forms oxygen and potassium chloride when heated. KClO₃(s) → KCl(s) + O₂(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct Answer
verified

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO₂ and H₂O, respectively, which are collected in the absorbers.

Correct Answer
verified

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Correct Answer
verified

Phosphorus pentachloride, PCl₅, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl₅.

Correct Answer
verified

Household sugar, sucrose, has the molecular formula C₁₂H₂₂O₁₁. What is the percent of carbon in sucrose, by mass?

Correct Answer
verified

Constitutional (structural) isomers have the same molecular formula but different structural formulas.

Correct Answer
verified

Methanol (CH₄O) is converted to bromomethane (CH₃Br) as follows: CH₄O + HBr → CH₃Br + H₂O If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr, what is the percentage yield?

Correct Answer
verified

Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO₃) ₂.

Correct Answer
verified

Balance the following equation: C₈H₁₈O₃(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
verified

A compound of bromine and fluorine is used to make UF₆, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct Answer
verified

Balance the following equation for the combustion of benzene: C₆H₆(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
verified

The formula CH₃O_0.5 is an example of an empirical formula.

Correct Answer
verified

One mole of methane (CH₄) contains a total of 3 × 10²⁴ atoms.

Correct Answer
verified

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules. A)118.15 g/mol B)99.15 g/mol C)78.07 g/mol D)59.08 g/mol E)50.01 g/mol

Correct Answer
verified

A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula.

Correct Answer
verified

Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride.

Correct Answer
verified

Exam 3: Stoichiometry of Formulas and Equations

Correct AnswerverifiedShow Answer

Constitutional (structural) isomers have the same empirical formula but different molecular formulas.

Correct AnswerverifiedShow Answer

Lead(II) sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form lead(II) sulfate and water. How many grams of hydrogen peroxide are needed to react completely with 265 g of lead(II) sulfide?

Correct AnswerverifiedShow Answer

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Potassium chlorate (used in fireworks, flares, and safety matches) forms oxygen and potassium chloride when heated. KClO3(s) → KCl(s) + O2(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct AnswerverifiedShow Answer

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO2 and H2O, respectively, which are collected in the absorbers.

Correct AnswerverifiedShow Answer

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Phosphorus pentachloride, PCl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl5.

Correct AnswerverifiedShow Answer

Household sugar, sucrose, has the molecular formula C12H22O11. What is the percent of carbon in sucrose, by mass?

Correct AnswerverifiedShow Answer

Constitutional (structural) isomers have the same molecular formula but different structural formulas.

Correct AnswerverifiedShow Answer

Methanol (CH4O) is converted to bromomethane (CH3Br) as follows: CH4O + HBr → CH3Br + H2O If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr, what is the percentage yield?

Correct AnswerverifiedShow Answer

Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO3) 2.

Correct AnswerverifiedShow Answer

Balance the following equation: C8H18O3(l) + O2(g) → H2O(g) + CO2(g)

Correct AnswerverifiedShow Answer

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Balance the following equation for the combustion of benzene: C6H6(l) + O2(g) → H2O(g) + CO2(g)

Correct AnswerverifiedShow Answer

The formula CH3O0.5 is an example of an empirical formula.

Correct AnswerverifiedShow Answer

One mole of methane (CH4) contains a total of 3 × 1024 atoms.

Correct AnswerverifiedShow Answer

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules. A)118.15 g/mol B)99.15 g/mol C)78.07 g/mol D)59.08 g/mol E)50.01 g/mol

Correct AnswerverifiedShow Answer

A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Potassium chlorate (used in fireworks, flares, and safety matches) forms oxygen and potassium chloride when heated. KClO₃(s) → KCl(s) + O₂(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct Answer
verified

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO₂ and H₂O, respectively, which are collected in the absorbers.

Correct Answer
verified

Correct Answer
verified

Phosphorus pentachloride, PCl₅, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl₅.

Correct Answer
verified

Household sugar, sucrose, has the molecular formula C₁₂H₂₂O₁₁. What is the percent of carbon in sucrose, by mass?

Correct Answer
verified

Correct Answer
verified

Methanol (CH₄O) is converted to bromomethane (CH₃Br) as follows: CH₄O + HBr → CH₃Br + H₂O If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr, what is the percentage yield?

Correct Answer
verified

Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO₃) ₂.

Correct Answer
verified

Balance the following equation: C₈H₁₈O₃(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
verified

A compound of bromine and fluorine is used to make UF₆, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct Answer
verified

Balance the following equation for the combustion of benzene: C₆H₆(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
verified

The formula CH₃O_0.5 is an example of an empirical formula.

Correct Answer
verified

One mole of methane (CH₄) contains a total of 3 × 10²⁴ atoms.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified